[lld] r353217 - [llvm-readobj] Display sections that do not belong to a segment in the section-mapping

[Matt Davis via llvm-commits]

Author: mattd
Date: Tue Feb  5 13:01:01 2019
New Revision: 353217

URL: http://llvm.org/viewvc/llvm-project?rev=353217&view=rev
Log:
[llvm-readobj] Display sections that do not belong to a segment in the section-mapping

Summary:
The following patch adds the "None" line to the section to segment mapping dump.
That line lists the sections that do not belong to any segment.
I realize that this change differs from GNU readelf which does not display the latter information.

I'd rather not add this "feature" under a command line option.  I think that might introduce confusion, since users would have to
make an additional decision as to if they want to see all of the section-to-segment map or just a subset of it.

Another option is to only print the "None" line if the `--section-mapping` option is passed; however,
that might also introduce some confusion, because the section-to-segment map would be different between`--program-headers`
and the `--section-mapping` output.  While the difference is just the "None" line, it seems that if we choose to display
the segment-to-section mapping, then we should always display the whole map including the sections
that do not belong to segments.

```
Section to Segment mapping:
  Segment Sections...
   00
   01     .interp
   02     .interp .note.ABI-tag .gnu.hash
   03     .init_array .fini_array .dynamic
   04     .dynamic
   05     .note.ABI-tag
   06     .eh_frame_hdr
   07
   08     .init_array .fini_array .dynamic .got
   None   .comment .symtab .strtab .shstrtab <--- THIS LINE
```

Reviewers: grimar, rupprecht, jhenderson, espindola

Reviewed By: rupprecht

Subscribers: khemant, emaste, arichardson, llvm-commits

Differential Revision: https://reviews.llvm.org/D57700

Modified:
    lld/trunk/test/ELF/linkerscript/segment-none.s

Modified: lld/trunk/test/ELF/linkerscript/segment-none.s
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/ELF/linkerscript/segment-none.s?rev=353217&r1=353216&r2=353217&view=diff
==============================================================================
--- lld/trunk/test/ELF/linkerscript/segment-none.s (original)
+++ lld/trunk/test/ELF/linkerscript/segment-none.s Tue Feb  5 13:01:01 2019
@@ -23,7 +23,7 @@
 
 # CHECK: Section to Segment mapping:
 # CHECK-NEXT: Segment Sections...
-# CHECK-NOT: .foo
+# CHECK: None {{.*}}.foo
 
 # DEFINED: Section to Segment mapping:
 # DEFINED-NEXT: Segment Sections...